Which way for one-way streets and reversible lanes?

Are one-way streets a good idea? What about reversible lanes? Is slower traffic safer, or does it create more pollution? Citizens in are debating these questions in the context of 15th Street in Logan Circle (which may return to two-way) and Connecticut Avenue in Cleveland Park (whose reversible lanes were the subject of recent debate). The discussion brings up many arguments, some valid, others myths, and some uncertainties.

At last week’s Dupont Circle ANC meeting, on the subject of the 15th Street reconfiguration, one citizen argued that slowing down traffic would increase pollution. After all, the longer cars spend on the block, the more they emit, right? Well, that’s what planners thought in the 1960s and was also used as justification for building freeways; the problem was, speeding up traffic through the cities encouraged suburban development, creating even more traffic and more pollution (“induced demand”). Would this happen in reverse? I tend to think so, but haven’t seen much hard data.

Here is an balanced article weighing both sides in the context of Richmond, VA. It makes the additional pollution-related rebuttal that one-way streets force drivers to circle larger distances to reach any particular location, since the most direct route may not be available.

It’s more clear that two-way streets improve safety; this Streetsblog article rebuts arguments that one-way streets are safer, and especially with cars getting cleaner over time, cutting pedestrian crashes should outweigh the pollution issue even if pollution will increase (which is unclear).

Some also argued that making the northbound-only 15th Street one way would increase traffic by adding cars southbound in the morning; others argued it would divert northbound traffic to 16th or 14th. These arguments largely cancel each other out; there can’t be more and less traffic at the same time. Jack Jacobson wrote a summary of some of the arguments.

I’m less sure about the right thing to do on this one. Connecticut Avenue is a major artery, and having suburban traffic use mixed-use boulevards like Connecticut is far superior to the alternative, bulldozing neighborhood fabric for land-value-destroying freeways. Still, many commenters on the DCist thread, some serious and some facetious, repeat the most debunked myth of all, that the real solution to traffic is to build even more lanes.

David Alpert is Founder and President of Greater Greater Washington and Executive Director of DC Sustainable Transportation (DCST). He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He lives with his wife and two children in Dupont Circle. Unless otherwise noted, opinions in his GGWash posts are his and not the official views of GGWash or DCST.